1. Field of the Invention
The present invention relates to a technical field of a lens barrel and an imaging apparatus, and particularly to a technical field in which the position of a centering lens is readily adjusted by using an imaging module to press the centering lens via a pressing plate and a packing and size reduction is achieved at the same time.
2. Description of the Related Art
Any imaging apparatus, such as a video camera and a still camera, includes a lens barrel having an imaging capability. In recent years, a variety of electronic apparatus, such as mobile phones, personal computers, and PDAs (Personal Digital Assistants), have been used in an increasing number of applications, and some of such electronic apparatus include a built-in lens barrel. Therefore, mobile phones, personal computers, PDAs, and other electronic apparatus including such a built-in lens barrel are also used as imaging apparatus for capturing images.
Some of such lens barrels have a configuration in which an outer enclosure houses a fixed lens, such as an objective lens, a movable unit including movable lenses, such as a focus lens and a zoom lens, an imaging device that converts an image capturing signal acquired through the fixed lens and the movable lenses into an image signal, and other components (see JP-A-11-311734, for example).
In a lens barrel including a movable unit, the movable unit moves in the optical axis direction to perform, for example, a zooming operation in which the imaging magnification is adjusted. When the movable unit moves between a wide-angle end and a telescopic end, the spatial frequency of the entire optical system (MTF: Modulation Transfer Function) changes in accordance with the position of the movable unit that has moved. In the lens barrel, the position of the fixed lens (centering lens) is therefore typically adjusted with respect to the optical axis so that the change in MTF is balanced across the range from the wide-angle end to the telescopic end.
For example, in a method for adjusting the position of the fixed lens in an image apparatus of related art, the fixed lens to be positionally adjusted is pressed against a predetermined surface by a plate spring-based pressing mechanism, and an adjustment jig is used to displace the fixed lens in a plane perpendicular to the optical axis.